Research was conducted to re-emphasize the importance of functional differences among jobs by showing how they help to better explain the income and status differences that are the main concern of recent stratification research. Status attainment, social class, and vocational psychological approaches to occupational and social differences were integrated into a multiple-market model, which suggests that the value of a determinant varies considerably by kind of work. Also the model's simultaneous use of situs as well as status of work provides a new perspective for developing a more comprehensive theory of social differentiation, for assessing social inequality more accurately, and for reducing inequality more effectively. A subsample of white men (black men, women, and men in artistic work were excluded) taken from a 1/1000 sample of the 1970 census was used to test the value of the multiple-market model in predicting income as opposed to the traditional one-market model. Results showed that the multiple-market model predicts statistical interactions between situs and other determinants of income. In contrast, the one-market predicts no interactions and no situs differences. (Author/TA)